Roll screen for cleaning root crops



June 2 ,1969 J. M. SILVER 3,451,084

ROLL SCREEN FOR CLEANING ROOT CROPS Filed April 25, 1967 Sheet of 2 JOSEPH W S I'E/"EE F/ G. 2.

AT TORNE Y5 June 24, 1969 J. M. SILVER 3,451,084

I ROLL SCREEN FOR CLEANING ROOT CROPS Filed April 25, 1967 v Sheet .3 of 2 INVENTOR. JOSEPH M. SILVER ATTORNEYS United States Patent 3,451,084 ROLL SCREEN FOR CLEANING ROOT CROPS Joseph M. Silver, Ogden, Utah, assignor to Ogden Iron Works Company, Ogden, Utah, a corporation of Utah Filed Apr. 25, 1967, Ser. No. 633,613 Int. Cl. A23n 13/00, 15/06; B07c /04 US. Cl. 153.11 10 Claims ABSTRACT OF THE DISCLOSURE A roll screen especially useful on beet pilers, or the like, for cleaning beets or other agricultural root crops. Alternate smooth and scrolled screening rolls extend transversely of the direction of travel of the beets along the screen from feed end to discharge end thereof and serve to spread the beets and accompanying trash transversely across the screen but longitudinally along the rolls making up the screen. Special cones at the ends of the rolls kick trash off the screen and tend to prevent roll damage due to solid material becoming wedged between the rolls. The spacing between rolls, the variable diameter of the smooth rolls, and the variable size and pitch of the scrolls on the scrolled rolls result in better dispersion of beets and trash longitudinally along the rolls, more effective cleaning of the smooth rolls, and improved trash removal.

Brief description This invention relates to roll-type screens for cleaning agricultural root crops and is particularly intended for use in cleaning sugar beets after harvesting.

In the processing of sugar beets it is important that as much of the accompanying earth, rocks and other trash be separated from the beets as is possible, so that a net weight of the beets can be determined by subtracting the weight of the material removed from the gross weight. If trash, including loose and adhering earth, dirt clods, rocks and other foreign material, is separated from the beets during this initial screening operation it does not need to be handled during other steps in the processing of the beets, thus reducing the demand on and increasing the efiiciency of the other cleaning processes, including the beet washing. Also, there is less chance that the processing machinery used will be damaged or jammed by rocks or other solid trash objects if the initial screening process efficiently removes many of these solid objects.

In the past there have been a number of roll-type screens developed for use in separating trash from beets and the like. U. S. Patent No. 2,976,550, for example, shows such a roll-type screen wherein alternate smooth and scrolled rolls are provided, with the scrolled rolls each having a plurality of reversely wound scrolls thereon. Also, in US. Patent No. 3,217,346 there is shown a roll-type screen wherein alternate scrolled rolls are provided with oppositely wound scrolls. While these previous roll-type screens have proven effective in separating a great deal of the trash from beets, there is still need for improvement. Some soils, for example, adhere to and are packed on the smooth rubber rolls and, unless they are effectively removed, reduce the screening efficiency. Also, the screens are subject to damage when an oversize solid trash object jams between the rolls. Under the best of conditions it has not been possible to remove all of the trash from the beets and it is desirable that more be removed.

It is an object of the present invention to provide a roll screen that more effectively removes all kinds of trash associated with beets or other such root crops than do roll screens heretofore known.

Another object is to provide such a screen that is durable and that is not as subject to damage from solid trash objects becoming wedged between rolls as are the roll screens heretofore known.

Principal features of the invention include special, staggered, spacing between rolls that results in the scrolled rolls cleaning the smooth rolls during operation to thereby further increase their cleaning efficiency; smooth rolls each having a variable diameter and a variable size and pitch of scroll construction on the scrolled rolls to increase screening effectiveness; and the special cone construction at the receiving end of a scrolled roll that increases screening effectiveness and reduces screen damage resulting from solid trash objects becoming wedged between rolls.

The smooth rolls are each positioned very close to one of the scrolled rolls so that mud caked on the smooth roll is scraped off by the scroll of the scrolled roll; a larger space along the opposite side, however, between the smooth roll and its next adjacent scrolled roll insures effective trash removal.

Special cones fitted to the receiving ends of the scrolled rolls, respectively, help in throwing out dirt clods, rocks, etc. that are conveyed longitudinally along the roll to the end; and these cones can be made freely rotatable with respect to their rolls to thereby reduce the possibility that solid trash objects wedged between rolls will damage the screen.

The size and pitch of the scroll on each scrolled roll and the spacings between rolls are varied to provide varying effects on the beets and trash handled. Thus, trash objects that will not be pulled through adjacent rolls at one point are conveyed along the scrolled roll and will frequently be pulled through, between the rolls, at a point where the scroll has a different size and pitch and where the spacing between the rolls is different.

There is shown in the accompanying drawings specific embodiments of the invention representing what are presently regarded as the best modes of carrying out the generic concepts in actual practice. From the detailed description of these presently preferred forms of the invention, other more specific objects and features will become apparent.

The drawings FIG. 1 is a side elevation view of a roll-type screen of the invention;

FIG. 2, a top plan view;

FIG. 3, an enlarged fragmentary plan view of four rolls of the invention;

FIG. 4, an enlarged, fragmentary, vertical section taken on the line of 4-4 of'FIG. 3, with an end cone shown freely rotatable;

FIG. 5, a view like FIG. 4, but showing the end cone locked to and rotatable with the hub and sleeve of the roll; and

FIG. 6, a view like FIG. 4, but showing another embodiment of end cone.

Detailed description Referring now to the drawings:

In the illustrated preferred embodiment, the roll-type screen of the invention is shown generally at 10, adapted to receive beets and trash at one end from a conventional conveyor belt 11 and adapted to discharge screened beets from the other end to a conventional conveyor belt 12. Since they are conventional, details of the conveyors, the supporting structure therefor and the driving structure are not here described in detail.

Roll-type screen 10 includes a frame made up of legs 13, interconnected at their tops by angles 14 and 15. Cross bracing between legs 13 and between angles 14 and 15, is provided as desired.

Each roll 16 or 17 of the screen has an axle shaft 18 that protrudes from each end of the roll and the ends of the axle shafts are each journaled in a bearing housing 19 that is secured in place on a frame member 14 by U-bolts 20, the legs of which project downwardly around the bearing housing and through holes in inwardly projecting legs of the angles 14. A frame member 14 is provided at each side of the screen for the purpose. Nuts 21 threaded onto the U-bolts secure the U-bolts and the bearing housings that are clamped thereby to the frame.

The rolls are arranged such that each smooth roll 16 is between a pair of scrolled rolls 17 (i.e., rolls having a projecting helical flight or scroll 17 wrapped therearound) and with the smooth roll closely spaced from one scrolled roll and more distantly spaced from the other.

The rolls 16 and 17 are all shown as being driven in one direction (see the appended arrows in FIG. 1) with their upper surfaces turning in the direction of travel of the beets. A motor 22, mounted on a platform 23 carried by an angle 14, drives a pulley 24 on the axle 18 of one scrolled roll 17 and the other scrolled rolls 17 are driven through sprockets 25 and connecting chains 26. Similarly, another motor 27, mounted on a platform 28 on the other angle 14, drives a pulley 29 on an axle 18 of a smooth roll 16. The other smooth roll 16 is driven by a chain 30 connecting sprockets 31 on the axles of the smooth rolls. While this drive arrangement has proven very satisfactory in some installations it is obvious that other drive arrangements could be used and that one or more of the rolls could be driven in a reverse direction, expecially if the screen is inclined rather than horizontal. Similarly, while the roll-type screen is shown here as the only device used for initial screening of trash from the beets, it should be obvious that the number of rolls making up the screen herein disclosed can be varied and that the screen can also be used in any desired series arrangement with others, such as the roll-type screens or the kicker screens shown by the aforementioned Patents Nos. 2,976,550 and 3,217,346, and that the screen can be arranged with the longitudinal axis of the rolls extending in the direction of beet flow over the screen.

The rolls 16 of the present invention are usually faced with a thick layer of rubber and are driven at a relatively slow speed, while the scrolled rolls 17 are driven at a relatively high speed. The outer diameter of each of the rolls 16 is rather abruptly changed to provide a center section 16a having a smaller outer diameter than the outer diameter of the ends 16b, but the surface of each section is substantially smooth and all sections are preferably faced with the thick layer of rubber.

Each scrolled roll 17 is made up of an axle 18, that is surrounded by a steel cylinder 33. Spacers 34 hold axle 18 centered within the cylinder, and a conical end member 35 is rotatably fitted over a close-fitted sleeve 18' that is welded to one end of axle 18 and abuts cylinder 33. A hub 36, slid onto close-fitted sleeve 18' and keyed to the sleeve by a key 37 fitting in groove 38 in the sleeve and slot 39 in the hub, is rotatable with the axle. A Snap-ring '40 fits in a groove 41 in the sleeve 18 and extends outwardly therefrom to keep hub 36 from sliding along the shaft.

Spaced holes 42 are provided through the outer edge of hub 36 and corresponding tapped holes 43 are provided in the conical end member, so that bolts 44 can be passed through holes 42 and threaded into tapped holes 43 to make the conical end member rotatable with hub 36 and shaft 18.

The conical end member can be either freely rotatable with respect to the cylinder 33, or it can be locked thereto through insertion of bolts 44, FIG. 5. In either case, as will be further explained, the conical end members assist in separating rocks and other trash from beets passed over the screen. When left freely rotatable, the conical end members tend to kick out solid trash objects jammed between rolls; and even when they are locked together, should a solid trash object become lodged between adjacent rolls at their ends and the key 37 shear, the conical end member and hub will become rotatable with respect to the axle, thereby tending to prevent serious damage to the screen.

A scroll 17' is helically Welded around each sleeve 36 in such a direction that, when the roll 17 is mounted on the frame as part of screen 10, the scroll will push material longitudinally along the roll in the direction of the conical end member. The scroll varies in size and in pitch, i.e. the length of its longitudinal travel per complete turn around the sleeve 36. The changes in scroll size correspond to the diameter changes of the smooth rolls, so that, when the rolls are arranged in a screen, a portion of smaller size scroll will be positioned alongside each larger diameter section of the smooth roll and a larger size scroll will be positioned alongside the smaller diameter section of the smooth roll.

The screen is constructed by arranging the rolls in side-by-side relation on the frame in the manner previously described. In a typical installation, the large end sections of the smooth rolls will have an outside diameter of 6 /2 inches and the smaller central section will have a diameter of 6 inches and the center section will constitute approximately one-half of the total roll length. The center section of the scrolled roll corresponds to the center section of the smooth roll will have a scroll, comprising a 4; inch diameter steel rod, welded thereto with a pitch of 11, i.e. the rod makes one complete helical winding around the roll section in a longitudinal distance of eleven inches. The end sections of the scrolled roll will each have a scroll comprising a W inch diameter steel rod with a pitch of 15, i.e. the rod makes one complete helical winding around the roll section in a longitudinal distance of 15 inches. The center-to-center distance between each smooth roll and its closely spaced adjacent scrolled roll is 7% inches and the center-tocenter distance between the smooth roll and its more widely spaced, adjacent scrolled roll is 7% inches.

In use, beets are discharged from the conveyor 11, that receives them from the growers trucks, onto the screen 10, are conveyed transversely across the rotating rolls 16 and 17, and are discharged onto the conveyor 12 to be transported for further processing.

As the beets and trash move transversely across the screen, the alternately wound scrolls on the successive scrolled rolls tend to move them back and forth across the screen longitudinally of the axes of the rolls. This spreads out the beets and trash and gives the varying size and pitch scrolls an opportunity to force the trash downwardly through the larger openings between rolls.

It has been found that scrolls having a larger pitch tend to more forcefully pull material through the screen, whereas the smaller pitch and larger size scrolls tend to better convey material longitudinally along the scrolls. However, as shown, the majority of the beets, being larger than trash objects, travel across the center portion of the screen, and, although a great deal of the trash is pulled through this center section, it is primarily trash that is carried to the sides to be forcefully pulled through by the flatter pitched scroll.

Rocks and other such trash objects propelled by the scrolls towards the ends of the rolls are deflected by the conical end members up and off the screen, As is seen in FIG. 6, the conical end member can also be provided with a stepped surface, wherein double conical surfaces 45 and 46 are interconnected by a shoulder 47. Should a rock or other such solid trash object become wedged between rolls, the conical end member, Whether freely rotating initially or becoming so after shearing of key 37, tends to rotate in the same directon as the adjacent smooth roll, also Working on the object, to thereby rotate the object out from between the rolls before any substantial damage can occur to the screen.

While the scrolls on the scrolled rolls are here shown as being continuous throughout the lengths of the rolls, they can also be discontinuous, if desired.

I claim:

1. A screen for use in separating trash from root crops,

comprising:

a frame;

at least one smooth roll having at least one axial section of reduced diameter carried by said frame;

a pair of scrolled rolls positioned on said frame parallel to and at opposite sides of said smooth roll, the size of the scrolls on the scrolled roll being larger along the sections of the scrolled roll that are opposite said sections of reduced diameter of the smooth roll; and

means for driving said rolls.

2. A screen according to claim 1, wherein:

the distance between one scrolled roll and the smooth roll is less than the distance between the other scrolled roll and the smooth roll.

3. A screen according to claim 1, wherein:

a conical end member is provided at the end of each scrolled roll toward which material is pushed by the scroll thereon.

4. A screen according to claim 3, wherein:

the conical end member is freely rotatable with respect to the scrolled roll,

5. A screen according to claim 3, further including:

means keying the conical end member with respect to the scrolled roll.

6. A scrolled roll for use in screens for separating trash from root-type crops, comprising:

a cylinder;

an axle shaft extending centrally through the cylinder and fixed thereto;

a scroll helically wrapped around the cylinder;

a conical end member abutting an end of the cylinder and having a surface flaring outwardly from the end thereof;

means positioning the hub on the axle shaft to hold the conical end member against the cylinder; and

means keying the hub for rotation with the axle shaft.

7. A scrolled roll, according to claim 6, further including:

means releasably interconnecting the conical end member and the hub for rotation together.

8. A screen for use in separating trash from root crops,

comprising:

a frame having a feed end and a discharge end;

a series of alternate scrolled and smooth rolls extending side-by-side transversely of said frame between said ends thereof so as to receive root crops from said feed end of the frame and discharge them from said discharge end of the frame, said rolls and the scrolls on the scrolled rolls being arranged to convey said crops along the rolls transversely of the frame and from roll to roll from the feed end to the discharge end of the frame;

and conical end members at alternate opposite ends of the scrolled rolls, flaring outwardly from the surfaces of said rolls and mounted on said rolls for free rotation relative thereto.

9. A screen in accordance with claim 8, wherein there are additionally provided removable keys between the conical end members and the rolls on which they are mounted, which keys, when in place, prevent rotation of said end members relative to said rolls.

10. A screen in accordance with claim 8, wherein the conical end members are provided with stepped conical surfaces.

'References Cited UNITED STATES PATENTS 2,604,206 7/1952 Armer 209-107 3,217,346 11/1965 Silver et a1, l53.11

FOREIGN PATENTS 3,446 8/1926 Australia. 308,822 10/1955 Switzerland.

EDWARD L. ROBERTS, Primary Examiner.

U.S. Cl. X.R. 

